Biomedical subjects
Publications and source records attributed to C S Choong.
A case of congenital varicella syndrome characterized by intrauterine growth retardation, ocular and neurologic abnormalities, but no cutaneous lesions is reported. This case highlights the risk of embryopathy from varicella infection during pregnancy in non-immune women.
BACKGROUND: There is no nationwide population-based study of the survival rate for liver cancer in Taiwan. Consequently, the true rate of liver cancer survival is unknown. Our aim was to determine the survival rate for liver cancer patients in Taiwan. METHOD: The Taiwan Cancer Registry was searched for liver cancer cases in 1987 and 2,558 cases were found. Of these, 485 lacked an identification number, 29 lacked documentation of age, 33 were metastatic, nine lived in Kinmen and Lienkiang Hsien of Fukien Province leaving 2,002 to be studied. With the help of identification numbers, we linked our cases with the Death Registry of the Department of Health, Executive Yuan, ROC, for the 1987 to 1992 period and calculated the five-year survival rate using actuarial life tables. For analyzing factors affecting the five-year survival rate, multivariate analysis with the Cox proportional hazards model was used. RESULTS: Of the 2,002 patients, 752 were diagnosed histopathologically and 1,250 patients were diagnosed clinically. A total of 15% of patients survived for five years or longer after diagnosis. Of those diagnosed histopathologically, 17% survived for five or more years, and of those diagnosed clinically, 13% survived for five or more years. The sex, age, residential area and ethnic origin did not affect the five-year survival rate significantly. Only diagnosis type affected the five-year survival rate significantly (p < 0.05). The 660 pathologically diagnosed liver cancer patients had a better survival rate than the 1,250 patients diagnosed clinically. CONCLUSIONS: The overall five-year survival rate for liver cancer in Taiwan was 15%. The prognosis for liver cancer patients in Taiwan is still unfavorable. The aim is to persuade affected patients to accept treatment.
Henoch-Schönlein purpura (HSP) is a systemic vasculitis with manifestations usually involving the skin, gastrointestinal tract, kidney and joints. Epididymitis is rarely seen as a complication of HSP. It is easily misdiagnosed as testicular torsion, causing the patient to undergo unnecessary surgery, because the patient may have complained of severe scrotal pain and swelling. We report a 5-year-old boy who was suffering from HSP associated with acute scrotal pain and swelling of the left testicle. No gastrointestinal signs were noted but severe joint pain, swelling and palpable skin lesions in the lower limbs and the buttocks were found. Prednisolone was prescribed and the boy recovered without surgical intervention.
Vigorous crying aids right ventricular ejection into the pulmonary artery. This phenomenon can differentiate functional pulmonary atresia from anatomic pulmonary atresia.
Internal hernia, herniation of the internal organs through defects in the intraabdominal cavity, is rare. Due to the rarity of this pathology and lack of the specific symptoms and signs, early diagnosis and treatment are always stressful to the clinician and misdiagnoses may occur in the emergency room. The prognosis of a patient with uncomplicated internal hernia is excellent. We report a 21-year-old Chinese man with internal herniation through a defect of mesocolon, presented as an impalpable abdominal mass which was shown only on imaging studies. In addition to the typical whirlpool pattern, a huge solid mass between the pancreatic tail and stomach was found under computed tomography (CT) scan. The major symptoms were intermittent epigastralgia and abdominal fullness that had bothered him for years. Physical examination results showed only mild epigastric tenderness. Computed tomography scans and exploratory laparotomy of the abdomen played vital roles during diagnosis. The herniated organ was a portion of jejunum with partial small intestinal obstruction.
Androgen effects mediated by the androgen receptor (AR) are essential for male reproductive development and virilization. Comparison of AR DNA coding sequence from five primate species, Homo sapiens (human), Pan troglodytes (chimpanzee), Papio hamadryas (baboon), Macaca fascicularis (macaque), and Eulemur fulvus collaris (collared brown lemur), supports their phylogeny with complete conservation of the DNA and steroid binding domain protein sequence. A linear increase in trinucleotide repeat expansion of homologous CAG and GGC sequences occurs in the NH2-terminal transcriptional activation region and is proportional to the time of species divergence. A serine phosphate/glutamine repeat interaction is observed where increasing CAG repeat length is associated with an increased rate of serine 94 phosphorylation. Disparity in the calculated and apparent molecular weight with CAG repeat expansion of an AR NH2-terminal fragment suggests self-aggregation with increasing glutamine repeat length into the pathological range. These results suggest that a CAG/glutamine repeat expanded during divergence of the higher primate species, which may have a direct effect on AR structure and support a common pathway in CAG trigenic diseases in the pathophysiology of neurodegeneration observed in X-linked spinal bulbar and muscular atrophy.
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Intracardiac tumors are rare in neonates. Most of these lesions are rhabdomyomas and they occur almost exclusively during infancy. Rhabdomyomas are commonly associated with tuberous sclerosis and often involve the brain, kidneys and pancreas; they are frequently multiple and originate most commonly from the ventricular septum. Surgical intervention is indicated for rhabdomyoma with either mechanical cardiac obstruction or dysrhythmias resulting in symptoms or sudden death. A newborn with diffuse rhabdomyomatosis over the right atrium, right ventricle and left ventricle of the heart complicated with congestive heart failure and intractable supraventricular tachycardia is reported herein. No tuberous sclerosis or other organ involvement was noted. The tumor was resected.
Pyomyositis is a primary infection of skeletal muscle. We report the case of a previously healthy six-year-old who suffered from pyomyositis in the right lower back. He presented with lower back pain and low-grade fever for one week. After a series of laboratory and imaging studies, the diagnosis of right multifidus muscle pyomyositis with abscess formation was made. The patient recovered rapidly after incision and drainage therapy, accompanied by antibiotic treatment. Methicillin-resistant Staphylococcus aureus was cultured from the abscess discharge. It was strongly suspected that herbal medicines and common cold medication the patient had been prescribed before admission to our hospital produced a masking effect that delayed the diagnosis.
BACKGROUND AND OBJECTIVES: Androgen insensitivity syndrome (AIS) is an X-linked disorder of XY males characterized by varying degrees of impaired masculinization. In many AIS cases, mutations have been identified in the coding sequence of the human androgen receptor (AR) gene which impair receptor function. Cases have also been reported in which reduced AR mRNA expression may contribute to AIS in association with AR gene mutations. The purpose of this study was to define the molecular basis of AIS in members of a family with clinical and laboratory features of partial androgen insensitivity (PAIS). DESIGN: Genital skin fibroblast (GSF) cultures were established from foreskin tissue for androgen receptor binding analysis. Genomic DNA was obtained from blood leucocytes for AR gene nucleotide sequence analysis. AR mRNA levels were determined in total RNA extracted from GSF cultures. PATIENTS: Three related subjects with perineo-scrotal hypospadias, bifid scrotum and microphallus were studied. The family pedigree of these subjects suggested an X-linked pattern of inheritance. Hormone assay results were consistent with AIS. MEASUREMENTS: AR binding capacity and affinity were determined in three subjects and compared with unaffected male controls. The coding sequence and 1.4 kb of promoter region of the AR gene were amplified in overlapping fragments by polymerase chain reaction from genomic DNA and sequenced. GSF AR mRNA was measured by a competitive PCR technique. RESULTS: In the PAIS subjects, AR affinity in cultured GSF was normal (Kd = 0.24, 0.30, 0.48 vs 0.27 +/- 0.07 (SD) nmol/l) but binding capacity was reduced (Bmax = 0.31, 0.36, 0.27 vs 1.26 +/- 0.37 (SD) fmol/microgram DNA). Sequence analysis of the CAG repeat polymorphism within exon 1 of the AR gene showed that both mothers were heterozygous at this locus, and that the three subjects had inherited the same allele. GSF AR mRNA levels were reduced in all three patients compared with controls (0.25, 0.74 and 0.74 vs 3.8 +/- 0.9 (SEM), range 1.8-7.3 amol/microgram total RNA). The nucleotide sequences of the entire AR coding region and of a 1.4 kb segment containing the promoter region were normal. CONCLUSION: Members of this family with clinical and biochemical evidence of X-linked partial androgen insensitivity syndrome demonstrated normal androgen receptor binding affinity and androgen receptor gene nucleotide sequence but reduced androgen receptor binding capacity and reduced androgen receptor mRNA. These results suggest that partial androgen insensitivity syndrome in this family may be caused by reduced expression of a normal androgen receptor gene.
Cockayne syndrome (CS) is a rare autosomal recessive disorder characterized by growth retardation, senile-like appearance, loss of subcutaneous adipose tissue, photosensitive dermatitis, microcephaly, deafness, pigmentary degeneration of retina, disproportionately long limbs, skeletal malformations with knee contractures and neurologic abnormalities. This is a description of a three-year-old boy with typical features of Cockayne syndrome complicated with tetralogy of Fallot, pneumonia and hepato-splenomegaly. He had been suffering from frequent attacks of pneumonia and had been hospitalized for several times since birth. Tetralogy of Fallot was diagnosed under echocardiography study and he died suddenly in hospital during a mydriatic procedure in the Ophthalmologic Clinic.
Group A streptococcal (GAS) septicemia is rare in occurrence but has a significant morbidity and mortality, whereas retropharyngeal abscess (RPA) is infrequent and it is most commonly found in children under the age of 6 years, with half of the cases occurring in children between 6 and 12 months old. This report concerns a case of GAS septicemia complicated with RPA. The patient, a five-year-old boy, was referred from a local medical department under the impression of meningitis. However, blood and throat cultures were both found to be positive for group A streptococci. Widening of the retropharyngeal space was noted in lateral neck roentgenography. RPA was confirmed by computed tomography (CT) of the neck. Ampicillin was prescribed for a period of four weeks. The patient was then discharged and oral form ampicillin was continued for four more weeks. No surgical incision and drainage was performed. Complete disappearance of the abscesses were noted via CT of the neck at an Outpatient Department follow-up.
The role of the androgen receptor (AR) in male sexual differentiation is revealed in part by the analysis of naturally occurring mutations in families with androgen insensitivity syndrome (AIS). We have investigated a family with partial AIS affecting three generations and have identified a G to A substitution in the AR gene at the fourth position 3' from the A of the ATG initiation codon changing the second amino acid residue from glutamic acid to lysine (EK2). Transient expression of the mutant EK2-pCMVhAR expression vector in COS cells revealed decreased translation with a 20-50% reduction in mutant protein relative to wild type AR by immunoblot analysis. The rate of dissociation of [3H]methyltrienolone from the EK2 mutant (half-time [t1/2] = 1.7 +/- 0.08 SE h) was increased compared with wild type AR (t1/2 = 2.4 +/- 0.11 h). Cotransfection studies using an androgen responsive luciferase reporter vector demonstrated a 50% reduction in transcriptional activation by EK2. These functional alterations are consistent with the partial AIS phenotype in affected males, corroborate the AR amino-terminal domain effect on kinetics of androgen binding, and provide physiological evidence for earlier translation experiments identifying the nucleotide sequence for optimal translation initiation.
Androgen insensitivity is an X-linked disorder of sexual differentiation resulting from mutations in the androgen receptor (AR) gene. In this paper, we report the clinical phenotype and molecular analysis of two siblings with severe partial androgen insensitivity due to a novel mutation in the ligand-binding domain of the AR gene. Binding studies using cultured genital skin fibroblasts demonstrated reduced AR affinity and binding capacity. Nucleotide sequence analysis of the AR gene of both siblings revealed a point mutation causing a glycine to arginine amino acid substitution at position 907 within a conserved region of the ligand-binding domain. A silent guanine to adenine substitution was also identified in the protein-coding region of exon 1. Using an expression vector in which the identified mutation was recreated by site-directed mutagenesis, the mutant receptor was found to have a reduced binding affinity (Kd = 3.06 nmol/L) for mibolerone compared with that of normal AR (Kd = 1.71 nmol/L) when expressed in COS-7 cells. In cotransfection experiments using CV-1 cells and a mouse mammary tumor virus-chloramphenicol acetyltransferase reporter system, the concentration of dihydrotestosterone required to induce half-maximal chloramphenicol acetyltransferase gene expression was 50-fold higher in cells transfected with the mutant AR complementary DNA than in cells transfected with normal AR complementary DNA. AR messenger ribonucleic acid levels in genital skin fibroblasts determined by both competitive PCR amplification and ribonuclease protection assay were decreased compared with normal values. Our studies demonstrate the importance of this region of the AR gene in normal AR function and AR gene expression.
The molecular basis for partial androgen insensitivity associated with adult onset spinal/bulbar muscular atrophy was investigated by transient transfection of human androgen receptor (AR) expression vectors containing increasing CAG repeat lengths in the first exon. An inverse relationship was observed between CAG repeat length and AR mRNA and protein levels. Trinucleotide repeat lengths of 43 and 65 associated with spinal/bulbar muscular atrophy decreased AR mRNA and protein levels but did not alter equilibrium binding affinity for [3H]R1881 or inherent transcriptional activity of AR, expressed as androgen-dependent fold induction of a mouse mammary tumor virus promoter-luciferase reporter vector. The findings indicate that glutamine expansion up to 66 residues in the NH2-terminal domain of AR does not alter AR functional activity. Rather, CAG repeat expansion in the region of the first exon reduces AR mRNA and protein expression. The study reveals a previously unrecognized effect of CAG repeat length on AR mRNA expression and a novel molecular mechanism for androgen resistance.
The technique of competitive PCR for measuring mRNA is used widely. Several variations of the method have been reported. We have evaluated some of the commonly used competitor types as part of our study into expression of the androgen receptor (AR). These included mutant, intron, deletion construct, and nonhomologous competitors, which were assessed with an emphasis on their ability to amplify the target with the same efficiency, as well as their capacity to form heteroduplexes with it. The effect of competitor size on amplification efficiency was also investigated. We found that the use of a common primer set did not guarantee equal amplification efficiencies among DNAs sharing the same primer sequences. For the competitors evaluated in this study, sequence length was the major determinant of amplification efficiency. The longest competitors were amplified with the least efficiency. Differences in amplification efficiencies were corrected for by standardizing the competitor against the target. Constructing competitors of different sizes to the target may not eliminate heteroduplex formation when they share common sequence with the target as with the intron and deletion type competitors. Such heteroduplexes may interfere with the analysis if they cannot be resolved from both the target and competitor. Use of a mutant competitor constructed by the conversion of one enzyme restriction site to another produced determinations that were independent of both heteroduplex formation and cycle number. A method is described for generating a mutant competitor with a single PCR.(ABSTRACT TRUNCATED AT 250 WORDS)
Multicystic dysplastic kidney (MCDK) is a common cause of abdominal mass in neonates. It is frequently associated with malformation of the contralateral kidney, such as ureteropelvic obstruction, etc. Because MCDK is usually functionless, it is important to evaluate the condition of the contralateral kidney. The presence of severe obstruction in the contralateral ureteropelvic junction is life-threatening and prompt treatment should be made to preserve the remaining renal function. We report on a neonate with left MCDK and contralateral ureteropelvic obstruction, presenting as anuria after birth, and also we review the literature.